9i NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
that may be in the paraffin. The fuel enters the carburetter through *
very minute jet and is mixed with a regulated intake of air to lorm an
explosive mixture before entering the cylinder.
The inlet and outlet pipes of the water cooling system should also
be fitted with strainers to prevent scum, weed and dirt coming in
from the sea. These strainers should be cleaned occasionally. All
parts should be kept as dry as possible especially the electrical equipment,
the wiring of which is insulated. The engine and boat must be kept
clean and no waste oil should be left in the bilge or in the drip tray
under the engine. A hand fire extinguisher and a bucket of sand are
kept handy to smother out quickly anything that may get ignited.
2. What is a magneto?
A magneto is a small dynamo which generates the current of elec-
tricity to provide the ignition necessary to explode the mixture in the
cylinders. The current passes along the insulated wire leading from
the magneto to the sparking plugs screwed into the tops of the cylinders.
The distance between the terminals of the plug is called the spark gap,
and the make and break contact at the magneto is so timed that ignition
of the compressed vapour in the cylinders takes place at the correct
moment and the explosion drives the piston. The terminals of sparking
plugs get sooted up-so they have to be unscrewed and wiped clean
occasionally.
3. You are in charge of a motor launch, describe the procedure of
. manoeuvring her alongside the accommodation ladder on the
starboard side of ship at anchor head to wind and tide. You
are approaching the ship on her port side.
I would shape a course that would counteract the effect of the tide.
This is done by watching the bearing of a stationary object and noting
whether the bearing draws ahead, astern or remains the same. If the
relative bearing does not alter the boat is making her course. I would
pass tinder the stern of the ship, not too close, and head up for a position
a little outside the ladder, slow down the engine by closing the throttle
a little, keeping enough way on the launch to overrun the tide. When
abreast of the ladder I would sheer alongside gently and get hold of the
boatrope, then put the engine into neutral.
4- •» man falls overboard from the launch, what action would you take
to, pick him up quickly?
Throw him a life-buoy, engine full astern and steer towards him.